Author Topic: john deere 440a with a 4239d slight knock after rebuild (Read 1355 times)

lumberjack48 · « **Reply #20 on:** February 05, 2012, 05:19:14 pm »

I would pull the head, most likely bent valve stems to, it all most has to be timing gears are set wrong.

I rebuilt a 292 Ford, when we went to start it, it blew out of the carb and sucked in the exhaust. [ don't laugh ] When i had put the timing chain on the motor was up side down.

kiko · « **Reply #21 on:** February 05, 2012, 10:50:57 pm »

Multiple bent push rods? Cam out of time or engine was not timed properly during valve lash adjustment. Top center number one: Intake and exhaust cly 1 , Intake cly 2 ,Ex cly 3. Rotate crank 360 deg, Ex cly 2 , Intake cly 3, Intake and Ex cly 4. Not sure of lash but propably Intake .014 Ex .018. If cam is timed properly vales should be overlapped on whish ever cly is at TDC. cam off a couple of teeth would cause engine failure but not bent push tubes. Hope this helps.

duckslayingpro · « **Reply #22 on:** February 05, 2012, 10:59:38 pm »

Well took head off and looked at valves everything looks to be good. A friend who used to be a john deere mechanic timed engine for me. I asked him about it. He seems to think the pushrods may have bent from the old block. I had to get a new crank, block, and head from schafers enterprises. The old block had a rod threw through it. News rods and everything installed in new block. I did reuse my pushrods and rocker arm and injection pump from old block. Oil presaure is holding around 30-40 lbs
I guess my next question is do you all think the pushrods could have.already been bent? The pushrods are not very visually bent. Rolling them on the table is only way i can see that they are bent.Wish i would have checked them before putting them in engine. Live and learn i guess... Guys thanks for all the help. This is a great forum!

sandhills · « **Reply #23 on:** February 06, 2012, 02:59:54 pm »

Those valves may resemble the pushrods in the fact it could be hard to tell if they are bent, the first thing I would do is "dummy" up the engine and crank by hand, obviously there should be no lock up what so ever. Did the top of the pistons show any sign of hitting the valves? Maybe not even possible on these engines?

kiko · « **Reply #24 on:** February 06, 2012, 08:09:09 pm »

duckslayingpro, I forgot to mention this the other night. With the head off you can roll the engine untill the number one piston comes up. Now drop four new push tubes into the cam followers on clys 1 and 2. If the cam is timed correctly the first second and forth push tubes will be the same height with the third one sticking up higher( counting from the fan) If this does not happen, roll the engine one revolution and look at the push tubes again if you still don,t have the three of them level with third one higher your cam is out of time. And yes I think the tubes could have been bent from the previous engine failure, but if valve lash was set correctly to begin with it is unlikely that they bent more to give the 1/8 gap you spoke of before . So, what I am trying to say is a slight bend in a pushtube can usally be adjusted out but should not be run for any extended period.

kiko · « **Reply #25 on:** February 06, 2012, 08:13:06 pm »

Duckslayer, I got it wrong The first three should be the same height with forth one sticking up higher. Did not catch the on the first proof read.

duckslayingpro · « **Reply #26 on:** February 06, 2012, 09:25:44 pm »

Ok. Thanks. I will check just to be sure.

duckslayingpro · « **Reply #27 on:** February 12, 2012, 10:02:37 am »

I looked at motor alittle closer before putting head back on. On number 3 piston (from the fan end) you could see where the valves have been kissing the piston. Next question is why? Valves not seated correctly from machine shop? Or something else? If motor was out of time shouldnt 2 pistons be getting toched by the valves at a time not just one? Thanks for any help!

kiko · « **Reply #28 on:** February 12, 2012, 10:56:19 am »

diagnosing on the phone is hard and is harder still on a forum. You make a good point about only one piston being touched. If the cam timing was good, and valve adjusted correctly. Crown clearance is also good. Just a thought, there must be a part that is mismatched such as the cam. The block and head that were sourced seperatly may not match the cam, but I am just fishing now. If the push rods were to long and valve adjusted properly that would not cause the valves to stay open as the piston came up. Only cam lift to high or lift at the wrong time. At this point I gotta know, so don,t forget to lets us know the solution to the puzzle!

snowstorm · « **Reply #29 on:** February 12, 2012, 12:23:56 pm »

valve has gotta be closed when piston is tdc. head been surfaced too many times?

so the valve is too far below the head. you never did answer jd parts ?? or maybe fit? turbo and non turbo pistons are different. turbo pistons are lower compression

duckslayingpro · « **Reply #30 on:** February 12, 2012, 12:38:05 pm »

I couldnt tell you if valves are john deere or not. I bought a fully loaded head that had been redone through shafers in wolf lake, il. I dont know what they use. Yes my kit came from john deere. Thanks again for all the info

kiko · « **Reply #31 on:** February 12, 2012, 12:40:16 pm »

snowstorm may be on to it, a thicker head gasket may be required if they make on for this application.

snowstorm · « **Reply #32 on:** February 12, 2012, 12:45:19 pm »

Quote from: kiko on February 12, 2012, 12:40:16 pm

snowstorm may be on to it, a thicker head gasket may be required if they make on for this application.

when i get out to the garage latter i will look in my jd tech manual pretty sure the head can only be surfaced a couple times. i threw one away once because of that. valves stuck down too far

duckslayingpro · « **Reply #33 on:** February 12, 2012, 01:12:27 pm »

Well i would appreciate the info. How could I tell if it has machined to much? My other question is if the head had been resurfaced to much woudnt all pistons be getting hit?

snowstorm · « **Reply #34 on:** February 12, 2012, 01:24:57 pm »

it would help if we had all the history on this thing. you said its a 239 the 440a used a 219. so what is it? what was done? how much was mix an match. come the whole story. could only one valve hit? maybe wrong connecting rod wrist pin bushing loose. in the head one valve seat replaced? seats ground more on the other cylinders?

duckslayingpro · « **Reply #35 on:** February 12, 2012, 01:53:21 pm »

It has a 4239 in it. It had a 4239 in it when i bought. Yes it would have had 4219 in it originally. The head and block I matched the casting numbers up with the new ones. The head was just supposed resurfaced with new valves, springs, etc. All connecting rods were replaced with same casting numbers. Wrist pin is tight. There wasnt any mixing everything was matched like it should be. Thank you.

duckslayingpro · « **Reply #36 on:** February 12, 2012, 02:09:45 pm »

Intake and exhaust valves are kissing the piston.

sandhills · « **Reply #37 on:** February 12, 2012, 04:13:55 pm »

Went back and read the original post, now I'm really digging here, on the cylinder that's hitting the valves is there any chance it has the wrong bearing on the connecting rod? Only reason I ask is that I overhauled a tractor once and yes it was my fault, I didn't plasti gauge the bearings, they sent the wrong ones and after warming up it would lose all oil pressure. Needless to say I got to go through the bottom end again, I can't hardly see how that would allow the piston to hit the valves but after ten or so minutes it could create a knocking sound. Just guessing, please let us know what you find.

snowstorm · « **Reply #38 on:** February 12, 2012, 05:25:55 pm »

this is for a 219 dont have a book for a 239. head can be surfaced a total of .030 distance from valve to head .057 and .037 .you can check cam lift with a dial indacator with the head on and valves adjusted. when the crank cam balance shafts were installed was the jd timing tool used?

? and a jd tech manual?

?? take lots of pictures need to see what we are working on

Bobus2003 · « **Reply #39 on:** February 12, 2012, 06:43:41 pm »

If you need a HeadGasket let me know.. I got a pair of them and a valve cover gasket that i don't need (Won't work on my 4045T). I'll let ya have them for shipping

News:

Author Topic: john deere 440a with a 4239d slight knock after rebuild (Read 1355 times)